Given pseudonym that's appropriate upset male journalist (9)
I believe the answer is:
nicknamed
'given pseudonym' is the definition.
'appropriate upset male journalist' is the wordplay.
'appropriate' becomes 'nick' (both can be verbs meaning 'steal' or 'take').
'upset' shows that the letters should be reversed in order.
'male' becomes 'man' (man is a kind of male**).
'journalist' becomes 'ed' (short for editor).
'man' back-to-front is 'nam'.
'nick'+'nam'+'ed'='NICKNAMED'
'that's' acts as a link.
(Other definitions for nicknamed that I've seen before include "with additional handle?" , "Given handle" .)